Use alias_attribute & alias_method to define parent-methods

app/models/project.rb

@@ -82,6 +82,8 @@ class Project < ActiveRecord::Base
   belongs_to :creator, class_name: 'User'
   belongs_to :group, -> { where(type: 'Group') }, foreign_key: 'namespace_id'
   belongs_to :namespace
+  alias_method :parent, :namespace
+  alias_attribute :parent_id, :namespace_id
 
   has_one :last_event, -> {order 'events.created_at DESC'}, class_name: 'Event'
   has_many :boards, before_add: :validate_board_limit
@@ -1521,14 +1523,6 @@ class Project < ActiveRecord::Base
     map.public_path_for_source_path(path)
   end
 
-  def parent
-    namespace
-  end
-
-  def parent_id
-    namespace_id
-  end
-
   def parent_changed?
     namespace_id_changed?
   end

spec/models/project_spec.rb

@@ -2095,6 +2095,13 @@ describe Project do
     it { expect(project.parent).to eq(project.namespace) }
   end
 
+  describe '#parent_id' do
+    let(:project) { create(:project) }
+
+    it { expect(project.parent_id).to eq(project.namespace_id) }
+  end
+
+
   describe '#parent_changed?' do
     let(:project) { create(:project) }